1520s, from Latin promulgatus, past participle of promulgare "make publicly known, propose openly, publish," perhaps altered from provulgare, from pro "forth" (see pro-) + vulgare "make public, publish." Or the second element might be from mulgere "to milk" (see milk (n.)), used metaphorically for "cause to emerge;" "a picturesque farmers' term used originally of squeezing the milk from the udder" [L.R. Palmer, "The Latin Language"]. Related: Promulgated; promulgating. The earlier verb in English was promulge (late 15c.).
